Redheaded people produce more of one type of melanin (phaeomelanin, which is yellow and red) than the other (eumelanin, which is brown). Redheads typically have a hard time tanning because the increased phaeomelanin, a red pigment, means their coloring will be red instead of brown. Learn more about the role of genetics in tanning.

Albinos are missing an enzyme called tyrosinase. As a result, their bodies cannot produce melanin. The missing pigment causes a lack of color in their skin, hair and eyes. Learn more about melanin.

Sunburns don't just age your skin -- they can actually damage your DNA, which can cause mutations that lead to cancer. Learn more about sun damage.